Newsweek has published a feature article exposing what many psychology researchers refer to as “the dirty little secret”: that antidepressant drugs do not work any better than placebo pills.

Author Sharon Begley notes that while antidepressants do in fact cause improvement in 75 percent of patients, so do placebo pills. In a landmark 1998 study, researchers Irving Kirsch and Guy Sapirstein found that a full 75 percent of antidepressants’ effectiveness could be attributed to the placebo effect.

Upon facing criticism for not including every study in their analysis, Kirsch and Sapirstein used the Freedom of Information Act to acquire data from all corporate-funded antidepressant studies submitted to the FDA. Two interesting facts emerged. First, the researchers found that 40 percent of studies conducted had gone unpublished, significantly higher than the 22 percent for other drugs.

“By and large, the unpublished studies were those that failed to show a significant benefit,” Kirsch said.

Second, when all studies were included, the drugs came out less effective, with placebo accounting for 82 percent of their effectiveness. The non-placebo improvement was only 1.8 points on the 54-point depression diagnostic scale. Sleeping better counts for six points.

The Newsweek article further notes that even those extra 1.8 points can be attributed to placebos: people in drug studies who experience side effects realize they are taking a real drug, which makes their placebo reaction stronger. The placebo effect also explains the increased effectiveness of higher drug doses, and why sometimes a second or third drug is effective when the first failed. It all comes down to belief.

A d v e r t i s e m e n t

These findings have serious implications for the entire premise on which antidepressant drugs rest: the chemical theory of depression. Other than the presumed effectiveness of antidepressants — a presumption called into question yet again by a recent study in the Journal of the American Medical Association — there is literally no evidence to support this theory.